New instrumentation for the selective visualization of specific nucleic acids and proteins greatly reduce the time and expense required by traditional visual-ization methods, while improving accuracy and ease of preparation for publication. We request funds to buy these instruments, the phosphorimager and fluorescence imager, as part of a single facility. There is currently no access to a fluor-escence imager whatsoever, and the single existing phosphorimager is obsolete, oversubscribed, not available on the ethernet network, and is scheduled by its owner (the Columbia-Presbyterian Cancer Center) to be relocated to a building several blocks away from the laboratories of its current users. Funds for new equipment are urgently needed to increase the productivity of the members of the user group, who are all NIH-funded faculty at the College of Physicians and Surgeons of Columbia University. Research projects include 5 on important human viral pathogens (HIV-1, Herpes simplex, and poliovirus), and others on subjects of biomedical importance which range from reaction mechanisms of Group II introns to pattern formation in chicks and mice. The versatile fluorescence imager is of special significance in view of fact that it will ameliorate the health hazards of radioisotopes and the escalating costs of radioactive waste disposal. The requested instrumentation will be in daily use by nearly all members of the user group.